The only advice I have is make sure you have a false sporer (pokemon with false swipe and spore) I can remember when I encountered my first RE shiny on soulsilver and first one on platinum the soulsilver was a neat little shiny weedle the odd story on that is I had just gone and healed my pokemon bought some Pokeball's in pewter city and went back to the viridian forest and ****** shiny weedle appeared and I caught it in a great ball after slightly weakening it, the floatzel is a much stranger story I had thought hmm I can chain on platinum but.... I don't have a pokemon with spore and false swipe so I thought DAMN I need a parasect since UT would take to long to get a Smeargle with those moves, so I went and after several hundred pokemon later I FINALLY came across my parasect so I caught it from my soulsilver in mewtwos cave traded it over to platinum and before I started to chain I saved in front of the grass, well, after 8 non shiny I think magnemite I go into another regular patch and think uhh this hunt is gonna go on forever and then I looked at my screen and BAM a shiny modest floatzel, I caught it THE SAME DAY AS PARASECT I was so surprised that only about 10-20 minutes after I traded over parasect I was so happy and now I take that parasect with me on all my shiny hunts, its helped me catch 10-15 chained shinies to date and that was in a time period of 3 months and they would pop up in chains after a long time, short time, or as a chain of 1 for my second shiny floatzel (this was jolly), and my shiny chain of 1 Shing bagon I had so much luck with shinies on platinum around then
Sorry for the long post, my only advice is always have a pokemon with spore and false swipe with you no matter what